[...]
I have a dial plan I am working on,
and right now it is getting very cumbersome with the blacklisting of
numbers, and the LookupBlacklist command isn't working as it is described,
at least how it is described in the description from CW and how it is set
up in Asterisk.

In * LookupBlacklist became a function that returns a value so you would
use it in an expression:
e.g.
exten => <ext>,n, GotoIf($[ LookupBlacklist() ] ? <a> : <b>)

In CW LookupBlacklist is an app (although the distinction between apps
and funcs is gone in CW so it really ought to return a value as well)
and its usage is:
e.g.
exten => <ext>,n, LookupBlacklist()
exten => <ext>,n, GotoIf($[ "${BLACKLISTED}" = "TRUE" ] ? <a> : <b>)

The CW description seems clear enough - although admittedly the example
could be improved!

[Description]
Looks up the Caller*ID number on the active channel in the CallWeaver database
(family 'blacklist'). Sets the variable BLACKLISTED to either TRUE if the
number was found, or FALSE otherwise.
Example: database put blacklist <name/number> 1